1. Field of the Invention
The present invention relates to a sheet treating apparatus capable of discharging sheets in the shape of a bundle, and an image forming apparatus equipped with such sheet treating apparatus.
2. Related Background Art
The conventional sheet treating apparatus 500, shown in FIG. 44 and capable of discharging sheets in the shape of a bundle, receives a sheet, on which an image is formed by an unrepresented image forming apparatus, by paired entrance rollers 2 and discharges the sheet by a large conveying roller 5 onto an intermediate tray 230, and, when plural sheets are stacked, the sheets are discharged as a bundle onto a tray 200 by rollers 180a, 180b. The roller 180b is elevated or lowered by a pivotally movable guide 150. When plural sheets are stacked on the intermediate tray 230, the sheets are pressed against a trailing end stopper 231 by a rotating elastic annular knurled belt 182, constituting a sheet trailing end aligning member, whereby the trailing end of the sheets is aligned.
The sheet may be composed of plain paper, a thin resinous sheet used as substitute for plain paper, a postcard, an envelope or a thin plastic plate.
Also the image forming apparatus can be a copying apparatus, a facsimile apparatus, a printer or a composite apparatus thereof.
However, when the sheet is discharged onto the intermediate tray 230 by discharge rollers 7, the trailing end of the sheet may be bent upwards in a curled state. In such case, the trailing end of the sheet comes into contact with the knurled belt 182, and is further bent upwards by the rotation of the discharge roller 7 whereby the sheet cannot be stacked on the intermediate tray 230 with alignment of the trailing end with other sheets, so that the alignment of the trailing end is unsatisfactory in such apparatus.
Also such upward bent sheet may be pinched between the knurled belt 182 and the intermediate tray 230, leading eventually to sheet jamming.